Genesis 21:29 YLT

²⁷  And Abraham taketh sheep and oxen, and giveth to Abimelech, and they make, both of them, a covenant;

²⁸  and Abraham setteth seven Lambs of the flock by themselves.

²⁹  And Abimelech saith unto Abraham, 'What 'are' they -- these seven lambs which thou hast set by themselves?'

³⁰  And he saith, 'For -- the seven lambs thou dost accept from my hand, so that it becometh a witness for me that I have digged this well;'

³¹  therefore hath he called that place 'Beer-Sheba,' for there have both of them sworn.